Category Archives: Brassica Vegetables

Cabbage Maggot; An old pest with limited options

The cabbage maggot (Delia radicum) is the larvae stage of the cabbage root fly which can cause severe damage to all Brassica crops. The adult cabbage maggot is a fly that is about half the size of a house fly and is grey in colour.

In the early spring, cabbage maggot flies emerge from the soil and the females lay small, white eggs ~2-10 cm below the soil line. Depending upon the temperature, eggs hatch 3-7 days later as larvae that immediately start boring Continue reading Cabbage Maggot; An old pest with limited options

Insect Pest and Crop Degree Day Update – May 26

Ontario DD Map May 25

Insect Degree Days

 

Weather Station Location Onion Maggot Seedcorn Maggot Cabbage Maggot Carrot Weevil Carrot Rust Fly Aster Leafhopper
(base 4°C) (base 4°C) (base 6°C) (base 7°C) (base 3°C) (base 9°C)
Harrow 468 468 342 285 535 189
Ridgetown 408 408 288 237 475 155
Delhi 391 391 271 222 455 141
Goderich 308 308 206 164 363 108
Guelph 284 284 186 145 342 87
Bradford*  318 318   205 172  369  112
Kemptville 304 304 217 179 356 119
Sudbury 168 168 105 82 210 47

 

Continue reading Insect Pest and Crop Degree Day Update – May 26

Preventing Yield Loss from Flea Beetles

Flea beetles are a common crop pest of crucifers in Ontario and overwinter as adults near the soil surface in debris and stubble from the previous crop. They typically become active with the first extended period of warm weather in the early spring as the leaf litter begins to thaw. The beetles feed on weeds throughout the field and have the ability to fly on calm days and will attack brassica seedlings as they emerge or transplants as they are planted.

Females will begin laying eggs in soil for about 30 days. Flea beetle larvae will hatch from eggs 12 days later and feed on the root hairs and taproots of seedlings. Left unchecked, adults will feed on leaves of transplants and the larvae will burrowing into the plant near the juncture of the root and stem. Continue reading Preventing Yield Loss from Flea Beetles

Samples requested for clubroot survey

By Travis Cranmer, Vegetable Crops Specialist
OMAFRA

First appeared in ONvegetables in The Grower, April 2017.

Clubroot, caused by the soil-borne pathogen Plasmodiophora brassicae can cause yellowing, stunting, wilting and club-like roots on susceptible Brassica species including broccoli, cabbage, canola and cauliflower. Clubroot causes an estimated yield loss of 10-15% in Brassica crops worldwide and in severely infested fields a 30-100% yield loss can occur. There are different races of clubroot known as pathotypes and the resistance of many cultivars is pathotype dependent.

severe clubbing, six weeks after seeding
Figure 1. Pak choy with severe clubbing, six weeks after seeding.

Continue reading Samples requested for clubroot survey

OMAFRA welcomes Travis Cranmer, Vegetable Crop Specialist

OMAFRA Vegetable Specialist Travis CranmerOMAFRA’s newest Vegetable Crop Specialist, Travis Cranmer, joins the ministry from the Vineland Research and Innovation Centre, where he worked on applied and molecular research in plant biology. With OMAFRA, he will work with vegetable crops including bok choy, broccoli, Brussels sprouts, cabbage, cauliflower, celery, chives, garlic, kale, kohlrabi, lettuce, leeks,  onions, shallots and spinach. Continue reading OMAFRA welcomes Travis Cranmer, Vegetable Crop Specialist

Got cabbage maggots? We’re interested!

Laura Stortz, OMAFRA / University of Guelph USEL student; Denise Beaton, OMAFRA Crop Protection Program Lead; Hannah Fraser, OMAFRA Entomology Program Lead (Hort)

The Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA) is collecting Cabbage Maggot larvae and pupae this summer as part of a national survey. We need grower cooperators for this survey! The goals of this survey are:

  1. To better understand the fly species responsible for damage to Brassicae vegetable crops.
    The larval stage of the Delia radicum fly species is thought to be the main culprit attacking Brassicae vegetable crops; however, there could be other species at play.
  2. Test for pesticide resistance in the fly species.
    Cabbage maggot is showing resistance to Lorsban (chlorpyrifos). This study’s results could lead to more efficient use of insecticides and support research on alternative control options.

Background: Continue reading Got cabbage maggots? We’re interested!

Got cabbage maggots? Invitation to brassica growers to collaborate in research

Article originally from HortMatters, Vol. 15, Issue No. 15, 15 July 2015

Did you know that a new research project on Cabbage Maggot in vegetable brassicas has just begun? The project pulls together a team to learn about the flies, Delia flies, which cause the pest known as Cabbage Maggot.Cabbage Maggot_larva 2 Continue reading Got cabbage maggots? Invitation to brassica growers to collaborate in research